A Turbo Detection Structure for Uplink Coded MC-CDMA System With Distortion Cancellation Capability

In this paper, a modified turbo detector is proposed, which, by combining a standard turbo detector with an iterative reconstruction method, cancels multiaccess interference (MAI) and clipping distortion in uplink coded multicarrier code-division multiple-access (MC-CDMA) systems. For clipping noise cancellation, signal reconstruction methods use nondistorted samples to reconstruct distorted samples; however, in MC-CDMA systems, the MAI causes these methods to not work properly. On the other hand, because of clipping, MAI-cancellation methods do not work properly. In this paper, we propose a joint iterative MAI and clipping noise-cancellation method, which is composed of a standard turbo detection structure and a clipping error estimator in each iteration. Furthermore, we investigate the convergence of the proposed method. Simulation results show that the proposed method improves the performance of coded MC-CDMA systems in the uplink in the presence of clipping distortion.